Metal foil, for example copper foil, is often laminated to a substrate. Resultant laminates are subjected to numerous processing techniques as well as inevitable wear and tear. In this connection, it is desirable to provide a laminate having high peel strength. High peel strength enables a laminate to maintain its structural integrity during processing (exposure to chemicals and various etchants) and over the course of normal wear and tear (heat degradation, physical agitation, and so forth).
Metal foils are typically treated to increase surface roughness and thereby increase the peel strength of resultant laminates. However, metal foils having increasingly high levels of surface roughness are subject to "treatment transfer", which is the undesirable migration of metal material from the metal foil to a dielectric substrate. Treatment transfer lowers the peel strength as well as degrading the insulating properties of the dielectric substrate. Treatment transfer also leads to unsightly yellow staining after the metal foil is etched. Accordingly, it is desirable to provide metal foil which not only exhibits high peel strength when incorporated into a laminate, but also does not affect the insulating properties of the dielectric substrate.
Since ammonium ions complex with metal ions when both are in solution, an increased concentration of ammonium ions in a given solution increases the solution's ability to solubilize metal ions. Solutions containing metal ions constitute waste which must be treated before being discarded. Generally, the higher the complexed metal ion concentration in a waste solution, the more difficult it is to treat the waste solution. It is therefore desirable to provide processes generating waste streams which are easy to treat.